Improving Spatial Reuse of Wireless LAN Uplink Using BSS Color and Proximity Information

With the density of wireless networks increasing rapidly, one of the major goals in next-generation wireless LANs (Local Area Networks) is to support a very dense network with a large number of closely deployed APs (Access Points) and crowded users. However, the CSMA (Carrier-Sense Multiple Access)-based medium access control of current wireless network systems suffers from significantly degraded performance when the network becomes dense. Recent WLAN (Wireless Local Area Networks) standards include measures for increasing spatial reuse such as BSS (Basic Service Set) coloring, but the schemes based on BSS coloring such as OBSS/PD (Overlapping BSS/Preamble Detection) have limitations in improving spatial reuse. In this paper, we propose a spatial reuse method for uplink which can utilize BSS color and proximity information to improve the efficiency of carrier sensing and thus spatial reuse. Specifically, through the BSS color and the proximity information, a node receiving a preamble can figure out how far the receiver of the ongoing traffic is located. This information is used to determine whether the node should aggressively start transmitting or defer its transmission to protect the ongoing transmission. Simulation results show that the proposed method outperforms existing methods in terms of throughput and fairness.

A CSMA Mechanism with Variable Collision Control and Priority Provision in Multichannel Mobile Ad Hoc Networks

Toward making the conventional carrier sense multiple access (CSMA) protocol transmit and control mobile ad hoc network systems, as well as reducing energy consumption, an adaptive multichannel multipriority two-dimensional probability detection and 1-stick joint control strategy carrier sense multiple access with variable collision duration and three-way handshake mechanisms (iCSMA for short) is proposed. Based on the conventional two-slot model of the CSMA protocol, iCSMA introduces a concept of collision duration (b), which divides the system’s timeslot into the duration of successful packet transmission (1 + a), the duration of collision (b + a), and the duration of the idle state (a) of the system. By employing iCSMA, the loss of the system could be reduced with a fine-tuned collision duration (b), which leads to improved performance compared to the conventional 1P-persistent CSMA protocol. Furthermore, a three-way handshake mechanism is introduced for monitoring the entire network system at a minimal cost of throughput. Toward a higher channel utilization rate, a multichannel and multipriority function is employed in the implementation of multiservice communication for the system. Besides, with an adaptive mechanism, the transmission probabilities p 1 and p 2 are reasonably set so that the system will not produce a complete collision under the condition of high load, and the throughput can also be stabilized. Based on the battery model, the lifetime of the system nodes (T) is extended. Both theoretical analysis and experimental results confirm the accuracy of the theoretical derivation.

Stochastic Network Calculus Model for Delay Distribution of Time Division Multiple Access and Carrier Sense Multiple Access in Underwater Acoustic Wireless Communication

Underwater Acoustic wireless communication becomes a popular research area for transmitting and receiving data between the communicators in the ocean environment. High accuracy in data communication can be succeeded by proficient modeling of carrier sense multiple access and time division access. For such innovations, the system has to proceed with an appropriate framework to make constant data traffic and limitations on start to finish data traffic delays. There are two major wireless communication multiple access methods that can be utilized in real-time underwater networks. One of the multiple access schemes is TDMA and another one is CSMA/CA. This paper concentrated on the modeling of TDMA and CSMA/CA also proposes the comparison of delay (end-end) of both multiple access protocols. The results using SNC to obtain delay bounds and are associated with simulation. The results show TDMA has a lesser efficiency than CSMA/CA in the acoustic environment.

Implementation of Persistent Relay Carrier Sensing Multiple Access Cooperative Communication Protocol for Ad Hoc Network

With the increasing demand for network coverage and congestion-free network traffic, cooperative communication is getting more and more attention from network researchers. Cooperation communication is explored in a number of ways. Such various techniques are studied and one method is discussed in this paper. PRCSMA- Persistent Relay Carrier Sense Multiple Access Protocol is a very efficient protocol that gives good results for cooperative communication. This protocol is implemented using NS2 (Network Simulator). Its analysis is carried out in this paper. This will be useful to compare the advantages of cooperative communication over regular wireless communication.

IEEE 802.11 based Medium Access Design for Wireless IoT-Blockchain Networks

Communication is a very basic essence of the blockchain network and must be carefully planned while integrating with IoT, where an extremely large number of devices are interconnected. In this work, blockchain nodes are assumed to use wireless channels to communicate among themselves and other elements of the IoT setup. These communications can be in unicast and broadcast manner where transmission latency and throughput are significant metrics that might jeopardize the overall system. This work is proposing a Medium Access Control (MAC) mechanism addressing these performance metrics and best suitable for wireless IoT-Blockchain system. The proposed MAC protocol is based on the widely used IEEE 802.11 protocol, Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) basic access.

CSNOMA: Carrier Sense Non-Orthogonal Multiple Access

In this paper, we investigate the possibility of the cross-layer design of a distributed random access scheme with considering physical (PHY) and multiple access control (MAC) layers, which utilizes the interference cancellation technique. In this regard, we propose a new multiple access protocol, named carrier sense non-orthogonal multiple access (CSNOMA). We consider the spatially randomly distributed interferers to realistically capture the effect of interference. The proposed protocol shows better area spectral efficiency than carrier sense multiple access (CSMA), as the node density increases. We also present a practical signaling design compatible with IEEE 802.11 DCF mode.

A LoRa-Based Linear Sensor Network for Location Data in Underground Mining

In this paper, we describe a LoRa (from “Long Range”)-based, linear sensor network we have developed for transmitting location information of personnel and equipment in an underground mine. The system is intended to be used during emergencies when existing communications infrastructure has failed. Linear networks comprise a sequence of relays that forward data to a common destination, the headend. Relays forward location information transmitted from tags carried by personnel or equipment. Relays will usually be put in place as investigators or rescuers enter the mine. LoRa is used both by the tags to communicate to the relays and by the relays to forward messages to the headend. We have implemented and tested this system, and have carried out simulations and analyses to determine its scalability, reliability and fairness. The need for robustness and reliability has led us to use flooding rather than unicast communication. We also use message sequence numbers and time-to-live fields to prevent broadcast storms. Contention is managed using a simplified Carrier Sense Multiple Access (CSMA) scheme. We also address fairness. When the network is under load messages may be dropped by relays making messages generated more hops from the headend more likely to be dropped than messages nearer the headend. We explore the relationship between unfairness, traffic load and number of relays. We also observe that a network of larger numbers of lightly loaded relays performs more effectively than smaller numbers of heavily loaded relays.

Performance Analysis of Resource Sharing During Downlink Multi-User Transmissions in CSMA/ECA Full Duplex WLANs

Full Duplex (FD) wireless communications is considered to be the next big step for future Wireless Local Area Networks (WLANs). Old (IEEE 802.11ac) and new (IEEE 802.11ax) WLAN features are expected to co-exist with FD operation. Some of these features include Downlink Multi-User (DL MU) transmissions at the physical layer while at the Medium Access Control (MAC) layer techniques such as the Transmission Opportunity (TXOP) sharing mechanism facilitates these multiuser transmissions. The traditional Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol is inadequate to support full duplex communications efficiently. A very promising adaptation of CSMA/CA and a powerful candidate as the basic channel access method for future WLANs is the Carrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA). In this paper, we provide an analytical model to assess the performance of resource sharing techniques in full duplex WLANs operating with the CSMA/ECA protocol. Our analysis is based on Markov chains to obtain an estimate of the achievable throughput of the Quality of Service Access Point (QAP) during DL MU transmissions.